Apparatus for washing and refilling boilers



Nov. 1, 1938. F, w, MILLER 2,135,407

APPARATUS FOR WASHING AND REFILLING BOILERS Filed March l4. 1938 REF/LL TEN/f REF/L1.

REF/LL w INYENTOR flank ZZ/Mzlen B I I f ATTORNEY.

Patented Nov. 1, 1938 UNITED STATES.

PATENT OFFICE APPARATUS FOR WASHING AND REFILLING BOILERS 13 Claims.

This invention relates to boiler washing and refilling systems, and while the principles thereof may be utilized in connection with the conditioning or reconditioning of stationary or other types :of boilers, its advantageous features are most desirable and effective when utilized for reconditioning locomotive boilers. A system designed and adapted for this particular purpose is therefore here illustrated and described as an exemplification of the purposes to which the principles of my invention are applicable.

In the reconditioning of locomotive boilers, it has long been the practice to blow off the steam and water from a boiler, store the blown off water 7 1 for washout purposes, utilize the blown off steam for heating fresh water for refill purposes, wash out the blown down boiler with the stored blown off water, and then refill the boiler with the heated fresh water.

In some instances, the blown off steam was delivered directly into the refill tank to heat the fresh water stored therein for refill purposes. In other instances, the practice which in later years has been more prevalent has been to deliver the I blown off steam to a heater of the open or closed type, more often the latter, to which fresh water was also delivered whereby the blown off steam Was condensed and the heat units thereof transferred to the fresh water which was delivered to the refill tank.

Such systems have given fairly satisfactory results when the locomotive boilers have been blown off and refilled in alternation, but when, as is frequently the case, several boilers are blown off simultaneously or consecutively and then several are similarly refilled, inherent defects in the principle of operation of such systems become magnifled and very low efficiency in operation is apparent.

For instance, in an installation where fresh water is heated in a condenser heater by the blown oif steam and delivered to the refill tank, if several boilers are blown off in succession, the amount of Water heated and delivered to the refill tank will greatly exceed the capacity of the tank and the surplus heated water will overflow from the tank to the sewer and be wasted. If the refill tank should be approximately full at the beginning of the blow-off operation, a relatively small amount of water heated by the blow-off steam will raise the tank level to the overflow point and all additional heated water delivered thereafter will be lost through the overflow. To obviate this large water loss, some installations have been equipped with a shut-off valve in the fresh water line to the heater condenser controlled by a float in the refill tank so that when the overflow level has been reached in the refill tank the delivery of fresh water to the heater condenser will be discontinued. In such case, however, the blown off steam delivered to the condenser will be released by a pressure relief valve and vented to atmosphere, with the result that the heat units of the blown off steam will be totally lost while the refill tank will stand full of water at a tempe-rature'far below that desired for refill purposes. In either event, whether the heated water be lost through the refill tank overflow or whether the blown off steam with its heat units be dissipated to atmosphere, the loss in heat or water, or both, is very substantial and the efficiency of the system is correspondingly diminished. V

In order to have sufiicient water in the refill tank to refill at least one or two locomotives, it has also been the practice in installations of the character under discussion to equip the refill tankwith a fresh water supply pipe which is controlled by a float located near the top of the tank so that whenever the water level in the tank dropsbelow the point for which the float is set, fresh water will be admitted to the tank to restore the predetermined desired high'level therein. The result is that the refill tank has but little additional storage capacity above this normal high water level. The first locomotive blown off will probably raise the waterlevel in the refill tank to the overflow point, and if additional locomotives are blown off before a refill is performed, either substantially all the heat units or most of the heat units and practically all of the condensing water produced by the blowing off of the additional locomotives will be lost.

When a refill takes place, the water therefor will be withdrawn from the refill tank at whatever temperature it may be at the time, but'as soon as the water level in the refill tank falls below the predetermined high water level for which the fresh water control float is set, cold water will be added to the tank thereby reducing the temperature of the refill water. If several locomotives are refilled in succession without an intervening blow off, the temperature of the refill water will be so reduced by the admission of cold fresh water that the refilling will be done with practically cold water or at least with water at a temperature far below that desired for refilling purposes.

When the refill tank has been thus depleted by successive refill operations, cold water will continue to besupplied thereto until the predetermined high water level has been reached, with the result that the tank will stand practically full of cold water which will not be heated to anywhere near the desired refill temperature during the next blow-off operation.

The above noted deficiencies in boiler washing and refilling systems have long been recognized by those skilled in the art, but prior to my present invention no remedy for these conditions has been available. The deficiencies, furthermore, have become more aggravated in recent years with the advent of the large capacity, high-pressure, modern locomotives which carry a steam pressure of approximately 300 pounds and have a boiler water capacity far in excess of anything previously known. The blowing down of one of these large locomotives produces about the same effect in a boiler washing and refilling system as the simultaneous or consecutive blowing down of two of the smaller locomotives. Consequently, the above mentioned defects and deficiencies in these systems are magnified by the large locomotives, because a large percentage of the blown off heat units are lost and wasted and the refilling of the locomotive has necessarily been done in a large percentage of the cases with water at a temperature much below that desired for refill purposes.

- The primary object of my present invention is to provide a method and apparatus for reconditioning or washing and refilling boilers which will overcome-the defects and deficiencies above mentioned by utilizing a much larger proportion of the blown off heat units from a boiler for refill water heatingpurposes than has heretofore been possible, and particularly where a large locomotive is blown oil' or two or more smaller locomotives are blown of! simultaneously or in suc-' cession.

Another purpose of my invention is to provide a system in which the refill water when required for refill purposes will always be available at a temperature suitable for refill purposes, that is,

in the neighborhood of 200 Instead of storing a largequantity of "water 7 in the refill tank at some indefinite but relatively ,low temperature, my invention contemplates the retention of a relatively small quantity of water temperature has been reached, fresh water is added to the refill tank under the control of a thermostatic valve so that the water is maintained at approximately that temperature, fresh water being added in proportion to the heat units transferred to the refill water in excess of said predetermined temperature. In this manner, the refill water is maintained at a temperature suitable. for efiicient refilling purposes, and the quantity of such heated water is determined by the volume of the blown off steam so that if a large locomotive or two or more small locomotives are blown off before a refill is required an adequate quantity of water to refill such locomotive or locomotives'at the requiste high temperature will be always available for that purpose. 7

The details of one preferred form of apparatus capable of accomplishing the aforementioned desirable purposes should be readily understood and its advantages appreciated from a consideration of the following description when considered in connection with the accompanying drawing.

Referring to the drawing:

The single figure is a schematic illustration of an apparatus by which the principles of my invention may be made effective.

Referring to the drawing more in detail, reference character I indicates a washout tank and 2 a refill tank, both of suitable size and construction for the purposes required. The blown off steam and water from a locomotive being blown down are delivered from the boiler through a blow-oil line 3 into a separator 4 by which the steam and water are separated, the blow-off water being delivered from the separator througha pipe 5 into the washout tank I where it is stored for future washout purposes, and the blown ofi steam being delivered from the top of the separator through a pipe 6 into one or more heat exchangers I and 8 which may be either of the closed or open type but are here illustrated as open type condensers. The sludge may be delivered from the condenser 4 through a pipe 9 and drain H to the sewer or other disposal means, a hand valve 12 being provided as a normal shutoif adapted to be opened when cleaning of the separator becomes necessary.

The water stored in washout tank I is withdrawn therefr'om when required by a washout pump I3,'-the suction side of which is connected to the tank through suitable piping [4, the discharge from the pump being delivered through a pipe line I5 to the washout line l6 extending to the roundhouse stalls and connected at its extreme end with a return circulating line I! discharging back into the tank I. Pipe I 4 is equipped with the usual check valve I8 and hand valve I9. Pipe I5 is provided with a hand valve 2|, and a cross connecting pipe 22 between pipe I5 and pipe 9 affords provision for delivering when valve 23 is opened.

The speed of washout pump I3 is controlled by a pressure governor 24 connected by pipe 25 with the delivery line I 5, and steam to operate pump 13 is supplied through a branch 26 from a main steam line 2'! extending from the power boilers of the installation.

Tempering of the washout waterso that it will not be delivered to the washout nozzle at a temperature higher than canbe comfortablyhandled by the operator is accomplished by admitting cold water to the intake of the washout pump through a branch line 28 emanating from a cold fresh water supply line 29. A thermostatic valve 3| in the branch 23 is thermostatically controlled through a suitable connection 32 by the temperature of the washout water delivered through the line 15. Surplus Water above a predetermined level in the washout tank is delivered to a sump or drain trench 32 by a siphon shaped overflow 33, the intake end of which is the overflow will be withdrawn from the coldest portion of the tank and the pitting of the lower portion of the tank walls occasioned by stagis maintained in the washout tank by admitting fresh water from the supply line 29 under the control of a balanced valve 35 arranged to be opened and closed by a float 36 connected with the tank at substantially the height at which it is desired to maintain a minimum water level.

The blown off steam delivered to the heat exchangers 1' and 8 through the pipe 6 from the separator 4 is condensed therein, and its heat units are transferred to the refill water by circulating the refill water through the exchangers during the blowing off operation. For this purpose a circulating pump 31 has its suction side connected by a pipe 38 with the refill tank 2 below the minimum water level maintained therein and its delivery side connected through a pipe 39 with the heat exchangers 1 and 8, the ends of the branch pipes 4| entering these condenser heaters being equipped with spray nozzles which disperse the water throughout the steam filled chambers, thereby enhancing the condensation of the blown off steam and the heating of the circulated water. From the heat exchangers the water and condensed steam are returned to the refill tank through a pipe line 42. Thus, it will be seen that the heat units of the blown off steam are transferred to the refill water stored in the tank 2.

A predetermined minimum water level is maintained in the refill tank by a balanced valve 43 interposed in a branch 44 from the cold water line 29, but the maintained level instead of being near the top of the tank, as has heretofore been customary, is near the bottom of the tank under the control of a float 45 by which the valve 43 is actuated. Normally, therefore, after a refill operation and before a subsequent blowoif operation, the refill tank will contain only a relatively small quantity of water, the minimum amount of which is determined by the float 45. When a blow-off operation now takes place, the refill water circulated from the tank through the heat exchangers will be heated therein by the blown off steam, thus raising the temperature of the small amount of refill water stored in the tank so that this water will soon be raised toa temperature approaching the boiling point.

When, however, the temperature of the refill water of the tank has reached approximately 200 F., fresh water is admitted to the tank through a branch 46 connected with the cold water line 29. The supply of water through branch 46 is regulated by a thermostatic valve 41 under the control of the thermostat .48 which is subjected to the temperature of the water in the tank. The admission of cold water to the tank counteracts or precludes any further rise in temperature of the refill water above that for which the thermostatic valve is set, with the result that as-the blow-off operation proceeds, the temperature of the refill water in the tank will remain substantially constant while the volume thereof will increase in accordance with the heat units transferred to the refill water by the blown off steam.

It will be manifest, therefore, that, instead of wasting water and heat units, as has heretofore been the case when the refill tank was substantially full at the beginning of a blowing-off operation, or instead of wasting the heat units of the blown off steam, as has heretofore occurred when the reaching of the overflow level in the refill tank occasioned the shutting off of the supply of condensing water, my novel method which contemplates a low water level in the refill tank at the start of a blow-off operation insures the utilization of all the heat units of the blown off steam for heating refill water and Without any wasting of water during any normal blow off. Furthermore, it insures that the refill water in the tank will be at approximately 200 which is a desirable temperature for refilling purposes or, in other words, the stored refill water is as hot as can be handled by the refill pump. I Should an unusual number of boilers be blown off simultaneously or in succession before a refill operation takes place, the capacity of the refill tank will of course eventually be reached, and in such event, loss or waste of heated water through the tank overflow is prevented by shutting off the further delivery of water to the tank through branch 46 through the instrumentality of a shutoff valve 49 interposed in pipe 46 and controlled by a float 5! located at the maximum Water level height of the tank overflow. This overflow is indicated on the drawing by reference character 52 and is adapted to discharge into a sump or trench 53 in the usual manner.

Under such circumstances, the refill tank will be substantially full of refill water at a temperature approximating 200 F., and if blowing off should continue beyond this point, no further water will be added to the tank, but the temperature of the large volume of stored water will be gradually increased by the continued transfer thereto of blown off steam heat units until the tank contents are at boiling temperature. Be-

yond this point, the surplus steam is permitted to escape to atmosphere through the vent pipe 50. This condition in which loss of heat units of blown off steam would occur could only arise under most unusual and infrequent circumstances where it became necessary to blow off an unusually large number of boilers before proceeding with any refilling.

The stored hot water in the refill tank is, Withdrawn therefrom for refilling purposes through a suction pipe 54 by a refill pump 55 which discharges through a pipe 55 into the refill line 5'! extending through the roundhouse. In the unusual event that the refill water in the tank should be in such close proximity to the boiling point that it could not be efficiently handled by the refill pump, the temperature thereof is reduced by admitting cold water to the suction side of the pump through a branch 58 from the cold water line 29, this admission being controlled by a valve 59 thermostatically influenced by a thermostat 6| located in the discharge pipe 56.

To maintain at all times a supply of hot water at the drops, the end of the refill line is connected with a return circulating line 32 which discharges through a spray nozzle into one of the heat exchangers, as 8 for instance. The exhaust steam from the washout and refill pumps is delivered through branches 63 and as, respectively, to an exhaust pipe 65 which is connected by a branch 66 with the heat exchanger 8 so that when no blow off is taking place the exhaust steam from the pumps will be condensed by the refill circulating water delivered from circulating line 62, which water and the steam condensed thereby will be returned through pipe 42 to the refill tank. As a precaution against the production of excessive pressure in the exhaust pipe 65- oil steam for heating refill water and which will insure after each blow-offoperation a supply of hot refill water approximating 200 in tempera-' ture. The waste and inefiiciencies ofprior prac- I tices are eliminated, with the result that my novel system is highly eificient and satisfactory in operation.

The structuraldetails illustrated and described are manifestly illustrative only and are capable of wide modification and variation without exmeans for circulating refill water from said tank 'quantity of refill water without reducing the" through said condenser and back to the tank to effect the heating of said water by the blown off steam delivered to the condenser, a fresh water line connected with said refill tank, and means controlled by the temperature of the refill water in the tank for admitting freshwater from said line to said refill tank upon the attainment of a predetermined maximum water temperature in said tank. V

2. In an apparatus of the character described, the combination of a refill tank, a closed refill water circulating circuit including a circulating pump and a heat transferring device, means for delivering blown off steam from a boiler to said heat transferring device to heat the water being circulated therethrough, and means controlled by the temperature of the refill-water in said tank for adding fresh water to said refill water after the refill water has been heated to a predetermined temperature to thereby increase the temperature thereof below said predetermined temperature.

3. In an apparatus of the character described, the combinationof a tank adapted to contain boiler refill water, means for maintaining a predetermined minimum water level therein, a

closed system for circulating said refill water, including a circulating pump and a heat transferring device, means for delivering the blown off steam of a boiler to said heat transferring device to heat the refill water being circulated V therethrough, means controlled by the tempera ture ofthe refill water in said refill tank for delivering additional water to the refill tank after a predetermined temperature of the refill water therein has been attained, and means for shutting off the delivery of such additional water 'when a predetermined maximum level of refill means controlled by the temperature of the refill water in the tank for delivering additional water to said tank only after said refill water has been heated to a predetermined temperature and in proportion to the additional heat units transferred thereto, means for shutting off the supply of such additional water to the tank when a predetermined maximum water level in the tank has been reached, a refill pump for delivering water from said tank for refill purposes, and thermostatically controlled means for tempering said refill'water by the addition of cold water thereto to prevent the refill water from being delivered at a temperature in excess of a predetermined maximum.

5. In an apparatus of the character described, thecombination of a refill tank adapted tocontain boiler refill water, means for maintaining a predetermined minimum water level therein, means for transferring heat units of the blown off steam from a boiler being blown down to the water in said tank, temperature controlled means for delivering additional water to said tank in proportion to the heat units transferred thereto but only after the refill water has been heated to a predetermined minimum temperature, means for shutting off such delivery of additional water to the tank when a predetermined maximum water level has been reached therein and irrespective of the temperature of said refill water, means for delivering water from said tank to a boiler for refill purposes, and means for automatically reducing the temperature of the delivered refill water to a predetermined maximum.

6. In an apparatus of the character described,

tank below said minimum water level therein for delivering fresh water to the tank in proportion to the heat units transferred thereto after a predetermined temperature of said refill water statically controlled means connected with said in the tank has been reached,,means1 for shut" ting off suchdelivery of 'fresh Water to the tank irrespective of the temperature of the refill water after a predetermined maximum water level in the tank has been reached, and means for delivering said heated refill water to a boiler for refill purposes. a

7. In an apparatus of the character described, the combination of a refill tank, a washout tank, arblow-oif line, a separator into which said blowoff line discharges, means for delivering said blow-01f water into said washout tank, a con denser, means for delivering the blown off steam from said separator to saidcondenser, means' for circulating water from the refill tank through said condenser and back to the tank to heat said water and condense said blown off steam, means controlled by the temperature of said refill water in the refill tank for delivering additional water to said tank, a washout pump connected with the washout tank, a washout line through which water is delivered by said pump for washout purposes, ,a refill pump connected with'said refill tank, a refill line through which said refill water is delivered for refill purposes, a circulating line through which water from the refill line is returned to said condenser, exhaust pipes from said pumps connected with said condenser to deliver exhaust steam from the pumps thereto, and means for delivering cold water to the intake of the refill pump when the temperature of the refill water exceeds a predetermined maximum.

8. In an apparatus for washing and refilling boilers, the combination of a hot water refill tank, a heat transferring device, means for circulating water from said tank through said device and back to the tank, means for delivering steam blown off from the boiler to said heat transferring device to heat the water being circulated therethrough, and means controlled by the temperature of the Water in said tank for adding water to the tank only when the temperature of the tank water exceeds a predetermined maximum.

9. In an apparatus for washing and refilling boilers, the combination of a liquid refill reservoir, a condenser, means for supplying steam blown off from the boiler to said condenser, means for circulating liquid from said reservoir through said condenser and back to the reservoir, and thermo-responsive means for delivering liquid from an outside source to said reservoir when a predetermined maximum liquid temperature is reached in said reservoir, whereby the liquid volume in the reservoir is increased without temperature reduction thereof.

10. In an apparatus for washing and refilling boilers, the combination of a liquid refill reservoir, a liquid heating apparatus heated by steam blown off from the boiler, means for circulating liquid from said reservoir through said apparatus and back to the reservoir to thereby heat said liquid, and means for increasing the volume of liquid in the reservoir while maintaining a predetermined temperature of said liquid, comprising a liquid supply pipe for the reservoir and a thermo-responsive device for admitting liquid to the reservoir through said pipe only when the liquid temperature in the reservoir exceeds a predetermined maximum.

11. In an apparatus for washing and refilling boilers, the combination of a liquid refill reservoir, means for adding heat units derived from steam blown off from the boiler to the liquid in said reservoir, and means including a liquid supply pipe and a thermo-responsivedevice controlled by the reservoir temperature for adding fresh liquid to the reservoir when the liquid therein exceeds a predetermined maximum temperature.

12. In an apparatus for washing and refilling boilers, the combination of a liquid refill reservoir, means for adding heat units derived from steam blown off from the boiler to the liquid in said reservoir, and means including a thermoresponsive device controlled by the temperature of the liquid in the reservoir for adding fresh liquid to the reservoir in proportion to the temperature of said liquid above a predfiermined maximum.

13. In an apparatus for washing and refillin boilers, the combination of a liquid refill tank, means for automatically maintaining a predetermined minimum liquid level therein, means for transferring heat units derived from steam blown ofi from the boiler to the liquid in said tank, thermo-responsive means controlled by the temperature of the liquid in the tank for delivering unheated liquid to the tank in proportion to the heat units transferred thereto after a predetermined temperature of the liquid in the tank has been reached, and means for shutting off the delivery of unheated liquid to the tank when a predetermined maximum liquid level in the tank has been reached and irrespective of the temperature of said tank liquid.

FRANK W. MILLER. 

